With continuous development of the touch sensing technology in recent years, mobile phones, tablet computers and numerous other display devices are provided with touch panels. Currently, common touch panels include resistive touch panels, capacitive touch panels, optical touch panels and the like. In the related art, a touch sensing electrode and a touch driving electrode in a mutual-capacitive touch structure made of indium tin oxide (ITO) material are arranged on the same layer, and touch electrodes in the same row or in the same column need a metal bridge structure for electric connection. Meanwhile, a metal grid has the advantages of higher conductivity, lower price and the like, and thus may be used as an alternative to the touch electrode made of the ITO material.
In order to overcome the above defect, the touch electrode prepared on a flexible substrate made of a cycloolefin copolymer (COP) is known in the related art. However, as COP is relatively hard, only the requirement on a display device with a fixed curvature can be met at present, but requirements of a flexible display apparatus that can be bent or curled cannot be met. To further improve the flexibility of the touch panel, it is known in the prior art that the touch electrode is prepared on a flexible substrate made of polyimide (PI). Polyimide is more flexible, thereby meeting the requirements of the flexible display apparatus that can be bent or curled.
However, when the touch electrode is prepared on the flexible substrate made of PI material, a metal portion of the touch electrode is likely to break during the use of a display device, particularly, a flexible display device due to different deformation rates of the metal portion and the organic material in the touch electrode, adversely affecting the touch performance.